Category Archives: App Notes

This company manufactures a portable sound system powered by specially designed bicycles ridden by a team of riders who together generate enough energy stored in a large ultracap module to power mics and amplifiers to make concerts possible anywhere. The ultracap module is set up in a series-parallel configuration with a capacity of more than 4000F.

Application: Valve Actuator

This company develops and manufactures innovative solutions in control technology for liquid and gaseous media flows with electrical actuation for high switching powers. The TPL-60/18x40F provides a fail-safe function by storing enough energy, in the event of a power failure, to return the valve to a defined safe position.

Notes:
1. With a 3V-4.2V battery and the high power rail at 5V, the DC:DC converter would be a boost. When the unit is first powered on, this must manage in-rush current to the supercapacitor by limiting the charging current. The TPS61200, TPS61202, TPS61020-8, and LTC3625 incorporate this feature.
2. If the battery voltage can be higher or lower than that on the high power rail, the DC:DC converter would be a buck-boost. Suitable examples include the LTC3442a or TPS63000, which also manage supercapacitor in-rush current. The TI boost regulators listed in above can also be used in this case, since they regulate as LDOs if Vbatt > Vo.
3. If LED flash is one of the functions on the high power rail, a high power LED flash driver can be used as the DC:DC converter. Suitable examples include the TPS61325, LM3550, CAT3224 or AAT1282.
4. If the GPRS module must operate at a lower voltage than the other high power loads, consider placing a regulator between the high power rail and the GPRS module.
5. If battery power is lost, the supercapacitor will support the entire unit – directly via the high power rail, and indirectly through the Power Select Switch for the low power and steady-state loads. This switch should be set to source all power from the supercapacitor if the battery voltage drops below a set threshold. The CAT6500 from ON Semi, Si4700DY from Vishay, or AAT4674 from AnalogicTech will perform this function.
6. An alternative architecture could supply the multi-channel buck converter directly from the supercapacitor, and do away with the Power Select Switch, but would be less efficient due to the losses in the DC:DC converter.
7. The dual cell supercapacitor module shown requires a balancing circuit to ensure that one cell does not go over-voltage. The simplest balancing circuit is a pair of resistors – one across each cell. The resistor value will depend on supercapacitor voltage and typical operating temperature. Resistor values are normally in the range 10KΩ – 39KΩ. To minimise leakage current, use an active balancing circuit, which will draw ~2 – 3μA (including that from the supercapacitor). The LTC3625 boost converter mentioned above has active balancing built in.
CAP-XX supercapacitors deliver these benefits due to their unique combination of:  very high power (low ESR) to minimize resistive voltage drop under load  high energy density (high capacitance) to minimize voltage drop under load  high cell voltage to maximize energy headroom  ultra-low leakage current (~1uA) to minimise unwanted energy losses  high temperature rating to support industrial grade performance and specification  low temperature operation to ensure unimpeded outdoor & refrigerated warehouse use  thin, prismatic form factor to fit into the smallest and slimmest enclosures  long operational life (low ESR rise rate and capacitance loss over time, long MTTF)  operational and disposal safety: UL 810A certification; RoHS, REACH and WEEE compliant; Halogen-free and Conflict metal free to support environmental requirementsFor more information on how to take your industrial handheld to the next level, visit the Tecate Group website: www.tecategroup.com, or call MFI, 607-786-4962.
Balance circuit
Supercapacitor
DC:DC converter
GPRS Module
High Power Voltage Rail
Power Select Switch
Multi -channel Buck
Steady-state & Low power loads such as CPU, RAM, flash memory, SSD, RTC, etc.
Typically @ 1.8V, 3.0V or similar
LED Flash
Thermal Printer
Audio Amp
High power, burst loads